The present invention relates to the storage and protection of products, with particular reference to the ensilage of agricultural products, particularly chopped forage or other products for livestock.
Chopped forage or other agricultural products, particularly for livestock, are known to be ensiled at the green state in concrete pits or in stacks on the ground and compressed so as to let out as much air as possible, and then to be covered with plastic sheeting, in order to protect the ensiled material, as well as to prevent air penetration, so that harmful surface fermentation may be avoided and only the so-called low fermentation, caused by a lactic fermentation flora consisting of anaerobic microorganisms.
Nevertheless, it has been noticed that covers used until present for these ensiled products do not satisfactorily fulfil their function when they are permeable to air, and particularly to oxygen, and that they do not prevent the ensiled material from fermenting or do not limit the fermentation of this material to the effect of anaerobic microorganisms only.
The invention aims at obviating this drawback and provides, to this end, a cover, named xe2x80x9csilo stopxe2x80x9d, for ensiled agricultural products, particularly for chopped silage, which cover consists of a single- or multilayer plastic sheet and is characterized in that at least one layer of the sheet consists of an insulating layer made of airtight, and particularly oxygen-tight plastic.
The plastic used for the insulating layer/s of the cover according to the invention may be formed by any type of polymers or copolymers, or mixtures thereof, wherewith a single-layer sheet, or at least one layer of a multi-layer sheet, at least substantially airtight and particularly oxygen-tight may be obtained.
According to a further characteristic of the, invention, the material used for the insulating layers of the cover for ensiled agricultural products may advantageously consist of polyamides, such as nylon, .or similar. However, other polymers may be also used, such as Ethyl Vinyl Alcohol (EVOH), Polyvinyl Alcohol (PVOH), Polyvinylidene Chloride (PVAL), EVAL, and others.
The insulating layer of the cover for ensiled products according to the invention may consist of one polymer (single-polymer layer) or of a copolymer, particularly of a mixture of at least one polyamide and one or more other polymers. Mixtures including 30% to 70% of polyamide and several combinations with other polymers insulating from air and oxygen are particularly preferred.
The xe2x80x9csilo stopxe2x80x9d cover for ensiled agricultural products according to the invention may only consist of the insulating layer, i.e. of one single-layer airtight plastic sheet, or may consist of two or more layers, for example coextruded layers, whereof at least one layer or possibly even more consist each of one insulating airtight plastic layer. In the case of a multi-layer sheet with at least two insulating layers, these insulating layers may be made of the same plastic material or of different plastic materials, all being airtight.
The above disclosure clearly shows that the cover for ensiled agricultural products according to the invention does not allowxe2x80x94thanks to its insulating layer/sxe2x80x94air, and therefore oxygen, to penetrate through the cover, thus preventing the fermentation of the ensiled product, or limiting it to lactic fermentation caused by anaerobic microorganisms.